A belt failure on the road is thoroughly bad news because changing a belt is not a feasible roadside repair. The belts can snap through sheer old age or wear and tear to the pulleys, which in turn causes the belt to run out of true and snap as a consequence. The classic sign of an ailing pulley is a belt that looks as if it is starting to shred. Checking the health of the pulleys requires the belt to be removed first before each pulley is rotated by hand and checked for roughness or undue rotational noise. Needless to say, belts that look as if they are starting to crack should be renewed.